The probes follow a 2014 ruling by the 2nd U.S. Circuit Court of Appeals that authorities have said could allow some individuals to avoid prosecution and that has already led to charges being dropped or reversed for 14 defendants.
John Casale, assistant special agent in charge of the FBI's complex financial crimes unit in New York, acknowledged the ruling could prevent some people from being charged in certain circumstances.
But he said his agents have not had to close any non-public investigations as a result of the ruling, which reversed the convictions of hedge fund managers Todd Newman and Anthony Chiasson.
That decision said that to prove insider trading, prosecutors must establish that a trader knew the tipper received something in exchange for the tip, like a quid pro quo involving money, and that the benefit was of "some consequence."
The court rejected the proposition that merely a friendship could constitute a benefit to the tipper. As a result, Casale said agents are increasingly focused on showing the tipper received a monetary or other tangible benefit.
"There's never been a slowdown in our process of thinking about cases," Casale said in an interview last week. "This was a hurdle we had to overcome."
It is unclear whether the FBI and prosecutors will be able to ultimately bring charges in those 30 undisclosed investigations. Such probes can often be closed without charges being brought.